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While providing these example architectures, this document will develop common definitions for the elements of the architectures by defining: 1 The elements of electrified propulsion architectures, including any dedicated power generation and distribution systems as well as energy storage elements. 2 The interfaces to/from the electrified propulsion system. 3 The interfaces within the electrified propulsion system. 4 Electrical energy management and storage architecture of an electrified propulsion system. ...The application of electric power for aircraft propulsion can take a variety of forms, ranging from partial electric to full electric. The introduction of electric engines to drive propulsors, along with the variety of available methods to generate electricity and store energy offers great degree of new design freedom for next-generation aircraft and aircraft architectures. ...This newfound design freedom exposes a need within the aviation industry to establish a common design language for electrified propulsion. While this need for a common design language is recognized, the intent of this document is to encourage innovation, providing reference architectures as a launching point for future work in this area.

This paper explores some of the many considerations which enter into the choice of a specific spacecraft propulsion system for a particular application. The environment and its influence on propulsion requirements are discussed in general terms, characteristics of several propellant combinations are presented and an example of a typical ambitious mission is used. ...A general conclusion is that the state of the art of spacecraft propulsion technology must advance on a broad front in the time period prior to project definition in order to provide the technological options which allow significant optimization of the complete project propulsion system. ...A general conclusion is that the state of the art of spacecraft propulsion technology must advance on a broad front in the time period prior to project definition in order to provide the technological options which allow significant optimization of the complete project propulsion system.

THE NUCLEAR turboelectric ion propulsion system operates as follows: 1. A nuclear reactor supplies thermal energy to a vapor boiler. 2. ...Electric propulsion systems can be used in a wide variety of space missions, including satellite sustainers, lunar cargo transport, and interplanetary missions.*

Aviation propulsion development continues to rely upon fossil fuels for the vast majority of commercial and military applications. ...With those challenges in mind, research and development of more efficient and electric propulsion systems will expand. Fuel-cell technology is but one example that addresses such emission and resource challenges, and others, including negligible acoustic emissions and the potential to leverage current infrastructure models. ...Requirements for greater flight time, stealth characteristics, and thrust-to-power ratios adds urgency to the development of efficient propulsion methods for applications such as UAVs, which looks to technologies such as asymmetrical capacitors to enhance electric propulsion efficiency.

This makes atomic energy attractive for aircraft propulsion, where it could combine high performance with large payload and long range. Chief obstacles in design of an atomic aircraft engine are development of light-weight shielding against deadly radiations; adequate cans to retain radioactive fission products; a pile capable of operating at high temperature and high thermal stresses; and a safe, flexible control mechanism.

General Electric is conducting a Propulsion Study for NASA as part of the Small Transport Advanced Technology (STAT) program. The General Electric CT7 is used as the current modern turboprop engine baseline.

The prop-fan propulsion system is being investigated as part of the NASA Aircraft Energy Efficiency program which includes both analytical studies and experimental tests.

It is compared with the chemical rocket and the nuclear turboelectric ion propulsion system. In developing the concept for this low-power rocket, NASA engineers concentrated on attaining low weight and high hydrogen temperature, and on solving problems concerned with automatic control and operation of high-temperature reactors.

A method that exploits certain properties of a recirculating gas has been investigated as a means of achieving a sustained accelerative vector force without either the expulsion of mass from or a reaction against an external mass by the accelerated body. A theory of operation is presented that defines the capabilities and limitations of the method, and which has resulted in functioning prototypes. The prototype devices require only a source of electric power and a means of cooling to achieve an internally generated, externally measurable accelerative vector force that is sustained for as long as power is supplied to the device.

Experimental data on performance and cooling from sea level and altitude firing tests of fluorine/oxygen mixtures with light-hydrocarbon fuels are presented. The majority of the work has been oriented toward pressure-fed rocket applications, with testing at 5000-lb vacuum thrust and 100-psia chamber pressure. Work in progress is at chamber pressures of 250 and 500 psia, being oriented toward pump-fed rocket applications. High delivered specific impulse levels have been demonstrated. One problem, apparently unique to these propellants, is that performance at the optimum mixture ratio is extremely sensitive to incomplete mixing.

To achieve this goal, NASA has analyzed a hybrid body wing aircraft with a turboelectric distributed propulsion system. The propulsion system must be designed to operate at the highest possible efficiency in order to meet the reduced fuel burn goal. ...High density components are required to minimize the weight of the electric propulsion system while meeting the high power demand. Minimizing the electric propulsion system weight helps to reduce the amount of fuel required for propulsion. ...NASA's N3-X aircraft design under the Research and Technology for Aerospace Propulsion Systems (RTAPS) study is being designed to meet the N+3 goals, one of which is the reduction of aircraft fuel burn by 70% or better.

This SAE Aerospace Information Report (AIR) establishes guidance for the specification of formulated lubricant properties which contribute to the lubricating function in bearings, gears, clutches, and seals of aviation propulsion and drive systems.

To present methods which, according to the consensus of the aviation propulsion community represented by SAE Committee E-34, allow the continued assessment of load carrying capacity of current chemistry products during periods of limited or nonavailability of previously used standardized methods.

This SAE Aerospace Information Report (AIR) reviews performance testing parameters for non-cleanable (often referred to as disposable) filter elements utilized in aircraft power and propulsion lubrication systems, including gas turbine engines and auxiliary power units (APUs), propulsion and transmission gear boxes, and constant speed drives and integrated drive generators (IDGs). ...This SAE Aerospace Information Report (AIR) reviews performance testing parameters for non-cleanable (often referred to as disposable) filter elements utilized in aircraft power and propulsion lubrication systems, including gas turbine engines and auxiliary power units (APUs), propulsion and transmission gear boxes, and constant speed drives and integrated drive generators (IDGs).

A trade study comparing the overall benefits in placing large payloads to GEO with the nuclear electric propulsion option shows superiority of nuclear thermal propulsion. The resulting savings in orbital transfer time and the substantial reduction of overall lift requirement enables the use of low-cost launchers for several near-term military satellite missions. ...An integral space power concept provides both the electrical power and propulsion from a common heat source and offers superior performance capabilities over conventional orbital insertion using chemical propulsion systems. ...An integral space power concept provides both the electrical power and propulsion from a common heat source and offers superior performance capabilities over conventional orbital insertion using chemical propulsion systems. This paper describes a hybrid (bimodal) system concept based on a proven, inherently safe solid fuel form for the high temperature reactor core operation and rugged planar thermionic energy converter for long-life steady state electric power production combined with NERVA-based rocket technology for propulsion.

The general problem of applying propulsion systems to supersonic aircraft is discussed briefly and it is shown that neither turbojets nor ramjets are entirely satisfactory when used by themselves. ...In order to avoid the confusion resulting from the comparison of propulsion system performance using the special parameters associated with each type of engine, performance is compared along operating altitude-Mach number paths in terms of thrust and specific fuel consumption only. ...The combined propulsion system arrived at offers promise of good performance, light weight, low cost, and simple installation.

Propulsion system controls have been steadily increasing in complexity to meet the regulation and limiting requirements of current and future turbine engines. ...This requirement further increases the sensing, computational and regulation functions of the propulsion system control. In the past, electronic controls have played a subordinate role because of the severe turbine engine flight environment and the computational needs of the engine could usually be met by hydromechanical components. ...With this insight, more timely planning and execution of state-of-the-art advances in propulsion system control technology can be accomplished to meet the functionability, performance, and confidence goals of future propulsion system hardware.

The Waste Management/Rocket Propulsion System appears capable of satisfying many propulsion requirements; for example, orbit change maneuvers, aerodynamic drag makeup, midcourse correction, terminal braking, and auxiliary and emergency propulsion. ...To date, spacecraft designers have considered life support systems and rocket propulsion systems as independent subsystems of a manned spacecraft. The Integrated Waste Management/Rocket Propulsion System concept developed by Rocket Research Corp. under NASA Contract NAS 1–6750, has demonstrated that human waste products can form a useful propellant ingredient and provide propulsion, as well as be an effective means of removing and sterilizing spacecraft waste. ...The Integrated Waste Management/Rocket Propulsion System concept developed by Rocket Research Corp. under NASA Contract NAS 1–6750, has demonstrated that human waste products can form a useful propellant ingredient and provide propulsion, as well as be an effective means of removing and sterilizing spacecraft waste.

Incorporation of an advanced technology, high-speed turboprop propulsion system into future air transports can achieve significant reductions in operating costs through large reductions in fuel consumption. ...The advantages of the propfan aircraft, in light of ever-increasing fuel shortages and fuel cost increases, have resulted in several NASA-sponsored research programs to verify propulsion performance and develop the required technology base. Continuation and escalation of these activities must be accomplished to ensure incorporation of the propfan into the next generation of commercial air transports.

ATR with extended precooling (Tout=100K) is examined in more detail. For propulsion systems including different types of engines, running simultaneously the concept of LH2 heat sink capacity concentration for turbojet air precooling is proposed.